These Supra ME Stiff 1/2" Trim Natural Bristle End Brushes Mounted on 3/32" Shanks miniature are the premium natural thin bristle brush on the market. Made in Soft and Stiff, these brushes are Made in the USA with solid steel ring construction for durability. Brush filaments are permanently anchored in the solid steel ring and uniformly distributed for even wear. Great for flat curved small and hard to reach surfaces. Made with natural animal hair. Maximum operating speed: 25,000 rpm.